This invention relates to a lock mechanism. The lock is primarily intended for a sliding door or window application.
In the following disclosure the door lock according to the invention will be described in the context of a mortice lock. However, it will be apparent to those skilled in the art that the lock mechanism in one or more of its possible forms could also be incorporated in a housing intended for rim or surface mounting. Consequently while the following description will describe a mortice lock any reference to lock housing or lock body should be read in the context of the housing or body being suitable for a mortice lock mounting i.e. within the door or a rim/surface mounting application.
Mortice locks for e.g. sliding doors provide a number of functions such as simple latching and unlatching of the door, so called day latching and deadlocking. To achieve these functions one lever is provided for latching, another lever or the like for day latching and a key cylinder for deadlocking. Visually the lock furniture associated with the lock takes on a “very busy” appearance resulting from the two levers and key cylinder. This also tends to restrict the size of the levers which can be used, otherwise the levers can be difficult to access and use. Thus, there are issues of appearance and user friendliness associated with existing locks. While these are manifested in the externally visible lock furniture the construction and arrangement of the lock mechanism dictates the number and/or type of external levers, snib etc. and position of the key cylinder.